Copyright © 2012 John Wiley & Sons, Inc. All rights reserved. 10 Energy Consumption

© 2012 John Wiley & Sons, Inc. All rights reserved. Think about energy use in your home:  Write down the main ways in which you use energy.  Write down ways in which your family conserves energy.  Tonight, look for Energy Star appliances, etc.

© 2012 John Wiley & Sons, Inc. All rights reserved. Overview of Chapter 10  Energy Consumption and Policy  Energy Efficiency and Conservation  Electricity, Hydrogen and Energy Storage  Energy Policy  Energy and Climate Change

© 2012 John Wiley & Sons, Inc. All rights reserved. Living Building Challenge  buildings&view=detail&mid=2F468CF4BA F468CF4BA &first=0&FO RM=NVPFVR&adlt=strict buildings&view=detail&mid=2F468CF4BA F468CF4BA &first=0&FO RM=NVPFVR&adlt=strict  NPR- the-dark-about-picking-a-light-bulb-this-faq- can-help the-dark-about-picking-a-light-bulb-this-faq- can-help

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Consumption and Policy  No energy sources are truly clean  All humans activities require energy  Heat & cool buildings  Illuminate buildings and streets  Plant, harvest, & ship food  100 years ago energy sources were local  Wood, peat, dung  Now they are worldwide  Fossil fuels, nuclear energy, electricity

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Consumption and Policy  Advantages of energy source  How concentrated it is  Versatility  Safety  Availability  Disadvantages of energy source  Hazard potential  Environmental damage  Cost  See Table 10.1 in text for details

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Consumption Worldwide  Differs between developing and developed nations  20% of world’s population use 60% of the world’s energy sources

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Consumption in US

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Efficiency  Amount of available energy in a source that is transformed into useful work  Ranges from 0–100%  Natural gas (cooking) ~100%  Natural gas (electricity) ~60  Incandescent bulbs ~2-3%  Fluorescent bulbs ~10%  Light-emitting diodes ~20% Pictured here

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Intensity  Energy Intensity- energy use per $ of GDP

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Efficiency  Super-insulated buildings use 70-90% less energy  NAECA sets national standards for appliances  Refrigerators built post are 75% more efficient than those build in 1975  Payback of $135/yr!

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Efficiency - Commercial Buildings  High-performing buildings pay for themselves  Energy costs = 30% of budget

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Efficiency- Power Company  Demand-side Management  Decreases demand for electricity  Cash rewards/incentives to customers who install energy-efficient technologies  Energy companies may give away free energy- efficient appliances, light bulbs, etc.  Benefits both customer and electric company

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Efficiency - Transportation  Most energy in gasoline is wasted  Energy lost in combustion to heat  Energy lost in braking  Energy lost in friction with road  Energy lost in moving weight of car (not passengers)

© 2012 John Wiley & Sons, Inc. All rights reserved.  Modern Vehicle Design  Use of Kevlar and plastics to reduce weight  Gasoline-electric hybrid engines (Prius) Regenerative braking recaptures lost energy Operate at lower temperatures  New Laws  By 2020, all passenger vehicles must have ave fuel efficiency of 35 mpg Including minivans, light trucks and SUVs Energy Efficiency - Transportation

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Efficiency - Industry  Cogeneration- production of two useful forms of energy from the same fuel  Most effective on small scale

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Conservation  Requires a change in behaviors and practices  Reduce commute length  Use public transportation or bike to work  Turn off lights when not in use  Reduce temperature on thermostat at night  Some changes would be difficult - e.g., removing subsidies  Allow product prices to reflect true cost of production (including energy costs)  Increase price of gasoline to represent true price

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Conservation

© 2012 John Wiley & Sons, Inc. All rights reserved. Electricity  The flow of electrons in a wire  Can be generated from almost any energy source  Energy source spins a turbine  Turbine turns a generator Bundle of wires spin around a magnet or vice versa  Spinning causes electrons to move in a wire = electricity

© 2012 John Wiley & Sons, Inc. All rights reserved. Electricity  Source of electricity can be hundreds of miles away  Environmental impacts are far away from those who use the energy

© 2012 John Wiley & Sons, Inc. All rights reserved. Hydrogen and Fuel Cells  Hydrogen gas (H 2 )  Comprised of two hydrogen molecules  Large amounts of available energy  Explodes when combined with oxygen releasing energy and forming water

© 2012 John Wiley & Sons, Inc. All rights reserved. Hydrogen as a Fuel Source  Advantages  Very high energy density  Can be produced from any electrical source Electrolysis (see illustration on next slide)  No greenhouse gases and few other pollutants  Can be use in vehicles  Disadvantages  Highly volatile (requires special storage)  Relatively inefficient

© 2012 John Wiley & Sons, Inc. All rights reserved. Electrolysis

© 2012 John Wiley & Sons, Inc. All rights reserved. Hydrogen Fuel Cell  Fuel cell  Device that directly converts chemical energy into electricity  Requires hydrogen from a tank and oxygen from the air  Similar to a battery, but reactants are supplied from outside source

© 2012 John Wiley & Sons, Inc. All rights reserved. Future Applications of Fuel Cells  Hydrogen Fuel Cells Vehicles  H not yet readily available as fuel source  61 H fueling stations in US

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Storage  Many energy resources are not available when we want them  Too little: Solar and wind can be intermittent  Too much: Large coal and nuclear plants are most efficient with constant energy output  Solution = storage of unused energy  Less than 100% efficient  With each conversion, less energy is available

© 2012 John Wiley & Sons, Inc. All rights reserved. Energy Storage  Superconducting Magnetic Energy Storage  Compressed Air Energy Storage  Electrochemical Energy Storage (Batteries)  Pumped Hydrogen Storage  Thermal Energy Storage  Kinetic Energy Storage (Flywheel)

© 2012 John Wiley & Sons, Inc. All rights reserved. US Energy Policy  Objective 1: Increase Energy Efficiency and Conservation  Requires many unpopular decisions  Examples Decrease speed limit to conserve fuel Eliminate government subsidies  Objective 2: Secure Future Fossil Fuel Energy Supplies  2 oppositions: environmental and economic

© 2012 John Wiley & Sons, Inc. All rights reserved. US Energy Policy  Objective 3: Develop Alternative Energy Sources  Who should pay for this? Gas taxes?  Objective 4: Meet the First Three Objectives Without Further Damage to the Environment

© 2012 John Wiley & Sons, Inc. All rights reserved. US Energy  policy policy